Kriengkrai Porkaew

Dynamic Queries over Mobile Objects

Increasingly applications require the storage and retrieval of spatio-temporal information in a database management system. A type of such information is mobile objects, i.e., objects whose location changes continuously with time. Various techniques have been proposed to address problems of incorporating such objects in databases. In this paper, we introduce new query processing techniques for dynamic queries over mobile objects, i.e., queries that are themselves continuously changing with time. Dynamic queries are natural in situational awareness systems when an observer is navigating through space. All objects visible by the observer must be retrieved and presented to her at very high rates, to ensure a high-quality visualization. We show how our proposed techniques offer a great performance improvement over a traditional approach of multiple instantaneous queries.

Social network user identification

Many people use more than one social network services (SNS). They create accounts for sharing both private and public information. These information are digital footprints that can be used to identify the owners. To identify the account identities, it is necessary to gather user information regarding their online behaviors. It can be used for marketing and customer interaction. In this paper, the architecture for matching accounts across multiple SNSs was proposed. It is designed for extensibility and configurability so that, given an account of a person on an SNS, it can be used to find other accounts belonging to the same person on any SNS. The system collects account information, such as username, friends, and interests from accounts on various SNSs and compare them using Jaro-Winkler distance algorithm. To be specific, this system focuses on finding Twitter accounts of a person given his/her Facebook account. An experiment of 138 user accounts are tested and its accuracy was 55%, which is almost twice better than a previous research on a similar situation.

AccAuth: Accounting system for OAuth protocol

When a user accesses a resource, the accounting process at the server side does the job of keeping track of the resource usage so as to charge the user. In cloud computing, a user may use more than one service provider and need two independent service providers to work together. In this user-centric context, the user is the owner of the information and has the right to authorize to a third party application to access the protected resource on the users behalf. Therefore, the user also needs to monitor the authorized resource usage he granted to third party applications. However, the existing accounting protocols were proposed to monitor the resource usage in terms of how the user uses the resource from the service provider. This paper proposed the user-centric accounting model called AccAuth which designs an accounting layer to an OAuth protocol. Then the prototype was implemented, and the proposed model was evaluated against the standard requirements. The result showed that AccAuth passed all the requirements.

Ticket model: a generalised model for internet-based three-party authorisation systems

Using web technology, a user may use a web browser to access a service on a web application that runs on a server. In many cases, a user needs to perform the task that requires the use of multiple web applications. Traditionally, a user needs to give his credentials to a third party website which leads to privacy and security issues. Though there are many existing protocols, most of them are ad hoc. Since the way a user accesses two independent web applications can be different, we define a web-based three-party communication model. After that, the well-accepted existing protocols are analysed. However, we found the common work flow in the communication though the protocols are in different scenarios. Therefore, we proposed the generalised model called Ticket model. Then, the details were discussed using a reference implementation. Finally, an accounting extension was added to the reference implementation as an example.

Answer Aggregation for Keyword Search over Relational Databases

with the amount of text data stored in relational databases growing rapidly, the need of the user to search such information is dramatically going up. Many existing approaches focus on finding a tuple matching a keyword query and return the result as a joining network of tuples of one or more tables. In this paper, we formulate an answer aggregation of keyword search over relational databases problem which merges related joining tuples from multiple tables to a single tuple to reduce redundancy in the results and improve the search quality. We developed an approach which exploits the tuple identity information for merging tuples rather than scanning throughout the results to find the common values. We further proposed a pruning algorithm which greatly reduces the number of redundant results after merging. We have conducted experiments extensively on two well-known databases (DBLP and IMDB). The experimental results show that the number of tuples in the results was dramatically reduced which noticeably improved the search quality while the merging time and the pruning time were relatively low when compared to the searching time.

Version Management of Hierarchical Data in Relational Database

Hierarchical data structure is organized into a tree-like structure represented by parent- child relationship. The parent can have many children but each child has only one parent. It is also known as one-to-many relationship. There are many types of data can be represented by hierarchical data structure such as organization structures and programs in academies. In some applications, there is necessary to keep historical data or version that need to be used. Temporal data management is used to handle historical data but cause high data space usage by storing every version data which decrease database efficiency. In this paper, we propose logical design to manage versions of hierarchical data in relational database that that may change overtime but historical data is still needed by reusing duplicated records. This conceptual design can avoid data redundancy and increase database efficiency.

Meaningful Interrelated Object Tree for XML keyword search

In the research field of XML retrieval with keyword-based approach, a variant of Lowest Common Ancestors (LCAs) have been widely accepted to provide how keywords are connected by ancestor relationship. However, returning a whole subtree or a partial subtree based on LCA nodes is insufficient for identifying how subtrees are conceptually related under different tree structure such as ID/IDREF. On the other hand, storing XML documents in the graph model can define richer relationships that the tree model cannot but the cost of enumerating result is very high. In this paper, we propose a novel Smallest Lowest Object Tree (SLOT) which keywords are connected through physical connections. In addition, to capture conceptual connections, we also propose the Smallest Interrelated Object Tree (SIOT) which extends ID/IDREF relationships based on SLOT. Finally, our experiment indicates that the proposed approach returns more effective and more semantic results for users.